Mumbai: Freak Covid-19 cases show need to study virus

After the recent discovery of cases where recovered Covid19 patients got mucormycosis and then tested positive for the virus too experts across segments have said that unusual cases must be documented and the sequencing of the virus must be done more frequently These could provide more clarity on such cases and aid researchVirus sequencing is important to understand if people are getting reinfected with the same or different strains of Covid19 Representation picProfessor of Global Health at the University of WashingtonSeattle Dr Subhash Hira who has extensive experience in managing mucormycosis in HIVAIDS patients in Africa said while referring to a midday report ldquoA teaching hospital in Mumbai is investigating 26 mucormycosis cases that came during MayJune Of these five patients had undergone four to six weeks of treatment for Covid19 and developed lsquoblack fungusrsquo within one to five days of discharge All five also tested positive for Covid19 which has started a debate among doctorsrdquoPossible ways of reinfectionldquoThe main concern was that makeshift Covid19 hospitals in Mumbairsquos suburbs could have been a source of black fungus for the five patients The floating mould that grows on moist ground and wet walls needs to be investigated as the likely source among others With regard to them being Covid19 positive there are two possibilities mdash one that the negative test at the time of discharge was due to a low viral load When these patients came in again with black fungus they could be experiencing a recurrence of the first Covid19 episode with a higher viral load Second it may be a reinfection that occurred within days of their discharge These two possibilities can be differentiated by sequencing the two virus samples if the first sample is preservedrdquo said Dr HiraDr Shashank Joshi consulting neurosurgeonHe added ldquoAs they get investigated further the cases will throw up many more solutions An unknown facet that needs to be investigated is whether or not they took the vaccinesrdquoDr Prashant Kewle ENT HOD ENT Anterior Skull base surgeon at Sushrut hospital Chembur said ldquoThere is a low possiblity that the first Covid19 infection will recur after a negative RTPCR test But a person may contract a new infection with another strain of the virus And RTPCR test will be positive againrdquoDr Wiqar Shaikh Professor of Medicine at Grant Medical College and Sir JJ Group of Hospitals said getting infected once by Covid19 does not guarantee lifelong immunity This is irrespective of negative tests and subsequently getting black fungus Dr Shaikh said that corticosteroid injections such as dexamethasone given to Covid19 patients which are known to suppress the immune system could be the primary reason for mucormycosis ldquoWe have also seen people who took two doses of the Covid19 vaccine and developed the infection and even got hospitalisedrdquo he said The classic example he added was of former IMA President Dr KK Agarwal who took both doses and yet developed Covid19 was hospitalised and died last monthDr Shaikh quoted a research paper published on June 14 in the journal lsquoNaturersquo which concluded that immunity after Covid19 may last up to 12 months and may be only slightly stronger after vaccination ldquoThe only way for Covid19 to stop infecting people repetitively is for the pandemic to go away completely which does not seem to be happening soon The other way out is for the entire population to develop lsquoherdrsquo immunity either the natural way or through vaccination of a large chunk of themrdquo Dr Shaikh saidDr Shaikh added that cases of repeated Covid19 in patients with mucormycosis become an extremely important subject for analytical study and research to know the underlying immunological reasons for such repeated infections and also to get the same documented and published for future referralsRecurring infections exceptionalldquoRecurrent infection from the same virus is not a rule but an exception as the human body forms virusspecific antibodies that make people resistant to recurrent infectionsrdquo said Dr Shashank Joshi consulting neurosurgeon Dr Joshi added ldquoThis phenomenon has been widely used by medical scientists to prepare vaccines which are either inactivated viruses or their components These vaccines are supposed to trigger antibody response Booster doses are supposed to augment the response further But we are seeing a recurring viral infection in the cases of Covid19rdquo ldquoMost probably a minor change in genetic material or proteins of the virus is responsible for such a phenomenon Frequent and mild changes in genetic sequence are called lsquodriftrsquo while major changes are called lsquoshiftrsquo Such pandemics occur as a result of shifts in genetic sequences However drifts will keep the virus and disease in active form for a few more years in the communityrdquo he concluded